1. Field of the Invention
The present invention relates to a construction machine such as a hydraulic excavator, the construction machine including a plurality of control valves, a plurality of remote control valves to operate the control valves respectively, and an operation-pattern selector valve to select one from combinations of the control valves and the remote control valves.
2. Description of the Background Art
The background art of the invention is described by an example of a small hydraulic excavator shown in FIG. 5.
The hydraulic excavator includes: a crawler-type lower travelling body 1; an upper slewing body 2 mounted on the lower travelling body 1 so as to be slewable around an axis X perpendicular to the ground; and a working attachment WA mounted on the front portion of the upper slewing body 2. The working attachment WA includes a boom 3, an arm 4, a bucket 5, and respective hydraulic actuators for operating the boom 3, the arm 4, and the bucket 5, namely, a boom cylinder 6, an arm cylinder 7, and a bucket cylinder 8.
The upper slewing body 2 includes an upper frame 9, on which an operation seat 10, a canopy 11, a control valve assembly 14, various operation devices, an engine, and relevant devices thereof are installed. The upper frame 9 includes a bottom plate 12 and a floor plate 13 as shown in FIG. 6. The floor plate 13 is disposed over the bottom plate 12 with a vertical distance.
The control valve assembly 14 is an assembly of multiple control valves, which are constituted of hydraulically-pilot-operated selector valves configured to individually control respective actuations of the hydraulic actuators, as described in Japanese Unexamined Patent Publication No. 2012-17553. In the specification, front and rear directions, and left and right directions are directions as viewed from the operator seated on the operation seat 10.
The control valve assembly 14 is mounted on the upper frame bottom plate 12 via a valve mounting member 15. The control valves are operated by the remote control valves 16, respectively. The remote control valves 16 are disposed around the operation seat 10 as shown in FIG. 6 by the two dotted chain line.
The operation-pattern selector valve 17 is a valve for an operator to select an operation pattern which is a pattern of respective combinations of the control valves and the remote control valves 16 in accordance with the operator's intention. The operation-pattern selector valve 17 is constituted of, e.g., a rotary selector valve (typically, called as “multiple valve”), including a tubular body 18, a shaft 19 held in the body 18 rotatably around the axis of the shaft 19, an operation handle 20 extending horizontally from the upper end of the shaft 19. A rotational operation is applied to the handle 20 to select one from a plurality of operation patterns.
As shown in FIG. 6, the operation-pattern selector valve 17 is mounted on the upper-frame bottom plate 12 through a bracket 21, similarly to one disclosed in, e.g., Japanese Unexamined Patent Publication No. 2008-31817, in a rear side of the control valve assembly 14 in such a vertical posture that the shaft 19 extends vertically and the handle 20 is located at the upper end of the shaft 19. Similarly, on the upper frame bottom plate 12 is provided a partition wall 22 so as to stand upright. The partition wall 22 partitions the space over the upper frame bottom plate 12 at a rear side of an underfloor space S, i.e., immediately behind the operation-pattern selector valve 17, thereby defining an engine room 23 under the operation seat 10.
There are respective hydraulic interconnections of: each of the remote control valves 16 and the operation-pattern selector valve 17; the operation-pattern selector valve 17 and each of the control valves of the control valve assembly 14; and each of the control valves of the control valve assembly 14 and each of the hydraulic actuators, through respective hoses. Specifically, as shown in FIG. 6 by the two dotted chain lines, each of the remote control valves 16 and the operation-pattern selector valve 17 are connected to each other through respective remote control hoses H1; the operation-pattern selector valve 17 and each of the control valves of the control valve assembly 14 are connected to each other through respective pilot hoses H2; and each of the control valves of the control valve assembly 14 and each of the hydraulic actuators are connected to each other by respective actuator hoses H3.
As to this type of arrangement, according to the conventional art disclosed in Japanese Unexamined Patent Publication No. 2008-31817, the operation-pattern selector valve 17 should be disposed in an upright posture at a rear side of the control valve assembly 14 and the handle 20 should be located at an upper position of the control valve assembly 14; the hose routing is therefore cumbersome.
Specifically, the arrangement of the operation-pattern selector valve 17 at a rear side of the control valve assembly 14, for instance, the arrangement of the operation-pattern selector valve 17 at an immediately front side of the partition wall 22 which is the rear limit of the underfloor space S, as shown in FIG. 6, requires for bending the remote control hose H1 suspending from the remote control valve 16 at a substantially right angle in a small clearance between the partition wall 22 and the operation-pattern selector valve 17 and connecting the remote control hose H1 to the operation-pattern selector valve 17 at the bent portion. This may decreases the flexibility in handling the remote control hose H1. Besides, the bending operation of the remote control hose H1 and the connection operation of the remote control hose H1 are cumbersome.
Furthermore, disposition of the operation-pattern selector valve 17 in the upright posture involves circuitously routing the actuator hose H3 as shown in FIG. 6, specifically, connecting one end of the actuator hose H3 to the control valve assembly 14 while guiding the other end thereof to each of the hydraulic actuators passing through the positions near the center of slewing. The actuator hose H3 is, therefore, required to be routed so as to pass through the small clearance between the operation-pattern selector valve 17 and the floor plate 13 while keeping away from the handle 20. In another alternative, the actuator hose H3 could be routed so as to pass not through the above clearance but beside the operation-pattern selector valve 17; however, this may involve interference of the actuator hose H3 with the pilot hose H2.